我写了下面的代码,用牛顿法通过逐次逼近找到平方根,但它没有给我正确的答案。可以请某人解释它吗?牛顿法求平方根的逻辑有什么问题?
#include<stdio.h>
#include<stdlib.h>
#define square(x) x*x
double rootByNewtonApprox(int n);
double improve(double n);
double average(double a,double b);
int goodEnough(double guess);
double guess(int n);
int number;
int main(void)
{
double root;
printf("\nEnter the number you want square root of: ");
scanf("%d",&number);
if(number<0)
number = -1* number;
root = rootByNewtonApprox(number);
printf("\nThe square root of %d is %lf\n",number,root);
return 0;
}
double guess(int n)
{
return n/2;
}
double rootByNewtonApprox(int n)
{
if(goodEnough(guess(n)))
return guess(n);
else
rootByNewtonApprox(improve(guess(n)));
}
double improve(double guess)
{
return average(guess,(number/guess));
}
double average(double a,double b)
{
return ((a+b)/2);
}
int goodEnough(double guess)
{
if(abs(square(guess) - number) <= 0.001)
return 1;
else
return 0;
}
现在,当我给n = 2
它给人的输出中nan
,当我给n = 9
它告诉segmentation Fault
。
见@ J.S。泰勒的回答如下代码。你遇到的是整数除法(不允许余数),所以你的一些函数没有返回正确的浮点值。 – 2011-04-30 06:19:14